Surface area of Cuboids |
Finding the surface area
of cuboids can appear on either the calculator or non calculator paper
of your maths exam. A common mistake is to confuse this topic
with finding the volume of cuboids; these are two totally different
questions! |
A cereal box has length 20
cm, height 30 cm and width of 8 cm. Find the surface area of the box. |
To find the surface are of
the box we need to find the area of each
rectangular face and add them all up. The area of the front face is 20 x 30 = 600 cm2. The area of the top face is 20 x 8 = 160 cm2. The area of the side face is 8 x 30 = 240 cm2. Now add these together to get 600 + 160 + 240 = 1000 cm2. IMPORTANT: This is not our final answer! Cuboids have 6 faces in total. We have only added three so far! For every front there is a back, for every top there is a bottom, and for every side there is another other side. This means we need to double our answer to get 1000 x 2 = 2000 cm2. |
A shoe box has length 30 cm, height 15 cm and width of 18 cm. Find the surface area of the box. |
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